Myricitrin promotes osteogenesis and prevents ovariectomy bone mass loss via the PI3K/AKT signalling pathway.

This study aimed to explore the effect of myricitrin on osteoblast differentiation in mice immortalised bone marrow mesenchymal stem cells (imBMSCs). Additionally, ovariectomy (OVX) mice were employed to examine the effect of myricitrin on bone trabecular loss in vivo. The effect of myricitrin on the proliferation of imBMSCs was evaluated using a cell counting kit-8 assay. Alizarin red staining, alkaline phosphatase staining were performed to elucidate osteogenesis. Furthermore, qRT-PCR and western blot determined the expression of osteo-specific genes and proteins. To screen for candidate targets, mRNA transcriptome genes were sequenced using bioinformatics analyses. Western blot and molecular docking analysis were used to examine target signalling markers. Moreover, rescue experiments were used to confirm the effect of myricitrin on the osteogenic differentiation of imBMSCs. OVX mice were also used to estimate the delay capability of myricitrin on bone trabecular loss in vivo using western blot, micro-CT, tartaric acid phosphatase (Trap) staining, haematoxylin and eosin staining, Masson staining and immunochemistry. In vitro, myricitrin significantly enhanced osteo-specific genes and protein expression and calcium deposition. Moreover, mRNA transcriptome gene sequencing and molecular docking analysis revealed that this enhancement was accompanied by an upregulation of the PI3K/AKT signalling pathway. Furthermore, copanlisib, a PI3K inhibitor, partially reversed the osteogenesis promotion induced by myricitrin. In vivo, western blot, micro-CT, hematoxylin and eosin staining, Masson staining, Trap staining and immunochemistry revealed that bone trabecular loss rate was significantly alleviated in the myricitrin low- and high-dose groups, with an increased expression of osteopontin, osteoprotegerin, p-PI3K and p-AKT compared to the OVX group. Myricitrin enhances imBMSC osteoblast differentiation and attenuate bone mass loss partly through the upregulation of the PI3K/AKT signalling pathway. Thus, myricitrin has therapeutic potential as an antiosteoporosis drug.

Ginsenoside Rb2 exhibits therapeutic value for male osteoporosis in orchiectomy mice by suppressing osteoclastogenesis and modulating NF-κB/MAPK signaling pathways.

Osteoporosis (OP) is a systemic disorder characterized by decreased bone mass as well as deteriorated microarchitecture. Although OP in men is common, it has received much less attention than that in women. Ginseng, a famous traditional herb in Asia, is used to strengthen and repair bones by invigorating vital bioenergy and maintaining body homeostasis in dietary intake and clinical applications. However, there is currently no study investigating the impact of ginseng and its active compounds on male osteoporosis. In this study, RNA sequencing and bioinformatic analysis were conducted to reveal the influence of Ginsenoside-Rb2 on RAW264.7 cells and its underlying signaling pathways. The potential anti-osteoporosis effects of Rb2 as well as its molecular mechanisms were elucidated in RAW264.7 cells and BMMs by TRAP staining, F-actin belt staining, qRT-PCR and WB. Moreover, orchiectomy (ORX) was utilized to demonstrate the influence of Rb2 on bone mass loss in vivo by micro-CT scanning, and H&E, TRAP, and IHC staining. The results suggested that Rb2 suppressed osteoclastogenesis and mitigated bone loss in orchiectomy mice through NF-κB/MAPK signaling pathways. These findings indicate that ginseng as well as its active component Rb2 have potential therapeutic value in the management of osteoporosis in men.

Quercetin protects against iron overload-induced osteoporosis through activating the Nrf2/HO-1 pathway.

AIMS: Eucommia is the tree bark of Eucommia japonica, family Eucommiaceae. In traditional Chinese medicine, Eucommia is often used to treat osteoporosis. Quercetin (QUE), a major flavonoid extract of Eucommia japonica, has been reported to have anti-osteoporosis effects. However, there are no studies reporting the mechanism of QUE in the treatment of iron overload-induced osteoporosis. This study set out to investigate the therapeutic effects of QUE against iron overload-induced bone loss and its potential molecular mechanisms. MATERIALS AND METHODS: In vitro, MC3T3-E1 cells were used to study the effects of QUE on osteogenic differentiation, anti-apoptosis and anti-oxidative stress damage in an iron overload environment (FAC 200 µM). In vivo, we constructed an iron overload mouse model by injecting iron dextrose intraperitoneally and assessed the osteoprotective effects of QUE by Micro-CT and histological analysis. KEY FINDINGS: In vitro, we found that QUE increased the ALP activity of MC3T3-E1 cells in iron overload environment, promoted the formation of bone mineralized nodules and upregulated the expression of Runx2 and Osterix. In addition, QUE was able to reduce FAC-induced apoptosis and ROS production, down-regulated the expression of Caspase3 and Bax, and up-regulated the expression of Bcl-2. In further studies, we found that QUE activated the Nrf2/HO-1 signaling pathway and attenuated FAC-induced oxidative stress damage. The results of the in vivo study showed that QUE was able to reduce iron deposition induced by iron dextrose and attenuate bone loss. SIGNIFICANCE: Our results suggested that QUE protects against iron overload-induced osteoporosis by activating the Nrf2/HO-1 signaling pathway.

Bioinformatics analysis combined with experimental validation to explore the mechanism of XianLing GuBao capsule against osteoarthritis.

ETHNOPHARMACOLOGICAL RELEVANCE: XianLing GuBao Capsule (XLGB) is often used to treat osteoarthritis (OA), osteoporosis, fractures, and other musculoskeleton disorders. However, the molecular mechanism of XLGB for treating OA is still unclear. AIM OF THE STUDY: This study set out to uncover the molecular mechanism underlying the treatment of osteoarthritis with XLGB. MATERIALS AND METHODS: Disease genes were obtained from CTD, DisGeNET, and GeneCards databases, and XLGB drug targets were obtained from ETCM and target genes predicted by XLGB metabolic components reported in the literature. Then we used the Venn diagram viewer to extract disease and drug intersection genes as potential therapeutic genes for Protein-protein interaction (PPI), GO terminology, and KEGG pathway analysis. Subsequently, we performed qRT-PCR, Western blot and histological analysis to validate the therapeutic effect of XLGB against OA and its molecular mechanism. RESULTS: A total of 1039 OA genes and 949 XLGB target genes were collected, and finally 188 potential therapeutic target genes were obtained. PPI network analysis indicated that the main target genes for XLGB to treat OA include Akt1, Mapk3, Il-6, Il-1ß, Ptgs2, Mmp9, etc. The results of KEGG and GO enrichment analysis suggested that XLGB may treat OA by anti-inflammatory and reducing extracellular matrix degradation. In vitro, XLGB down-regulated the expressions of Mmp3, Mmp9, Mmp12, Mmp13, Cox-2, Il-6, increased the expression of Collagen II and Sox9. Mechanistically, XLGB inhibits the activation of PI3K/AKT/NF-κB and MAPK pathways. Moreover, the results of animal experiments indicated that XLGB reduced cartilage destruction, bone resorption, and synovitis in osteoarthritic rats. CONCLUSIONS: XLGB has a protective effect against OA by suppressing PI3K/AKT/NF-κB and MAPK signaling. Our study provides a theoretical basis for XLGB in the treatment of osteoarthritis.